The subsurface of the upper Earth's crust is used for the exploitation of raw materials or the extraction and storage of energy. In the context of the German energy transition and the associated phasing out of coal and nuclear energy, the use of the underground will have to increase through energy storage, e.g. of green hydrogen or gas in pore and cavern storage facilities. Likewise, deep geothermal energy will be used more intensively, especially for the heat supply of cities. These changes of utilization concepts will raise new questions about the safe development and long-term stability of the storage facilities.

A key factor here is the rock stress in the upper Earth's crust and its changes due to human-induced activities. These lead to changes in rock properties and thermal, mechanical and hydraulic conditions. Geomechanics also plays a central role in the search for a deep geological repository for high-level radioactive waste. Several factors that are influenced by the stress state must be taken into account in the site selection process, the construction plans and the investigation of long-term stability. These include e.g. the excavation damage zone, the hydraulic permeability of the host rock, the self-sealing capacity, effects of seismic events and the possible reactivation of faults as migration paths for fluids and radionuclides.

Because stress magnitude can only be determined at specific points, researchers - including those at the German Research Centre for Geosciences in Potsdam GFZ - are developing geomechanical models that are used to calculate forecasts for areas without stress data. "This enables us to estimate the contemporary continuous three-dimensional stress field for regions of interest. However, we have to calibrate our models, and for this we need a basic stock of stress magnitude data in the bedrock measured at specific locations," states Sophia Morawietz from Section 2.6 Seismic Hazards and Risk Dynamics at GFZ. In a recently published study with colleagues from the GFZ, Australia and the Technical University of Darmstadt, she now presents the first comprehensive and publicly accessible stress magnitude database for Germany and surrounding areas with currently 568 data records. This has been accomplished within the framework of the project SpannEnD which is funded by the BMWi.

This database is the consequent extension of the database of the World Stress Map Project, in which so far only information on stress orientations is systematically compiled. "This study is a blueprint for the expansion on a global scale and we are making an important contribution to improve the reliability of geomechanical prognosis models" states Oliver Heidbach, geophysicist and co-author of the study.

Original study: Morawietz, S., O. Heidbach, K. Reiter, M. O. Ziegler, M. Rajabi, G. Zimmerman, B. Müller, and M. Tingay (2020): An open access stress magnitude database for Germany and adjacent regions, Geothermal Energy, DOI: 10.1186/s40517-020-00178-5

Scientific contact:

Sophia Morawietz
Section 2.6 Seismic Hazard and Risk Dynamics
Helmholtz-Centre Potsdam
German Research Centre for Geosciences GFZ
Telegrafenberg
14473 Potsdam
Phone: +49 331 288-2814
E-Mail: sophia.morawietz@gfz-potsdam.de

Dr. Oliver Heidbach
Group Leader
Section 2.6 Seismic Hazard and Risk Dynamics
Helmholtz-Centre Potsdam
German Research Centre for Geosciences GFZ
Telegrafenberg
14473 Potsdam
Phone: +49 331 288-2814
E-Mail: oliver.heidbach@gfz-potsdam.de 

Media contact:

Dr. Uta Deffke
Public and Media Relations
Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Telegrafenberg
14473 Potsdam
Phone: +49 331 288-1049
Email: uta.deffke@gfz-potsdam.de